In article , Andy Evans
wrote:
60 years ago saw the introduction of the Western Electric 300A and 300B
direct-heated power triode, RCA 45, 50, and 2A3 directly-heated power
triodes, and RCA 27, 56, 76, 6P5, 6J5, and 6SN7 family of
indirectly-heated triodes. Sixty years later, these devices continue to
be the lowest distortion amplifying elements ever made. No pentode,
bipolar transistor, JFET, or MOSFET has ever approached the distortion
performance of mid-Thirties triodes. In addition to low distortion in
the absolute sense, the distortion spectra of triodes is favorable, with
a rapid fall-off of the upper harmonics. (This is not true for beam
tetrodes, pentodes, or solid-state devices, which are intrinsically less
linear.)

Could you be more specific by what you mean above? Under what specific
conditions of use, signal powers, etc, are you making the above comments?

Slainte,

Jim

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